Magnesium Citrate

Magnesium citrate is a highly soluble magnesium salt formed by the complexation of magnesium ions (Mg²⁺) with citric acid. Due to its excellent aqueous solubility, it is frequently used in dietary supplements to increase systemic magnesium levels, supporting a wide range of physiological processes that depend on this essential mineral.

• Chemical Composition: Magnesium citrate is the trihydrate salt of magnesium and citric acid, with the empirical formula C₆H₅MgO₇·3H₂O (molecular weight ≈ 214 g/mol).
• IUPAC Name: The IUPAC name is magnesium 2‑hydroxypropane‑1,2,3‑tricarboxylate trihydrate.
• Molecular Structure: It consists of a central Mg²⁺ ion coordinated octahedrally by three citrate anions, each providing two carboxylate groups for chelation.
• Physical Properties: The compound is a white, hygroscopic powder, highly soluble (> 100 g/L at 25 °C) in water, producing a mildly acidic solution (pH ≈ 5.5) due to the citrate component.
• Solubility: Its high solubility distinguishes it from other magnesium salts (e.g., magnesium oxide) and underlies its rapid gastrointestinal absorption.

• Production Method: Commercial magnesium citrate is produced by reacting food‑grade magnesium oxide or hydroxide with citric acid derived from fermented corn or sugarcane.
• Manufacturing Process: The reaction yields a crystalline trihydrate that is milled, dried, and micronized for supplement use.
• Natural vs. Synthetic: Natural dietary sources of magnesium (e.g., leafy greens, nuts, legumes) provide magnesium bound to organic acids, but the isolated citrate form is synthesized to guarantee consistent elemental magnesium content and purity.
• Quality Control: Good Manufacturing Practice (GMP) facilities employ recrystallization and filtration to remove heavy metals and residual solvents.
• Third-Party Testing: Third‑party testing (e.g., USP, NSF) verifies assay potency (≥98 % magnesium citrate) and absence of contaminants, essential for clinical efficacy and safety.